Sciency Words: Astrobiology

sciency_words_slimSciency Words is an ongoing series here on Sci-Fi Ideas celebrating the rich and colorful world of science and science-related vocabulary. For today’s special Alien August edition of Sciency Words, we turn our attention to the term:


Astrobiology: it’s not science fiction. It’s a young but important branch of science focused on the study of alien life. The word literally means “star-life-study” in Greek.

Given that we have yet to discover alien life, you might be wondering what do astrobiologists actually do? What exactly are they studying? Well, at the moment they primarily study life on Earth.

Wait a minute, you might be thinking, how is that different from regular biology? The difference is that when astrobiologists study terrestrial organisms, they’re trying to identify qualities that might be universal to all life, as opposed to qualities that may only be distinctive to Earthly life.

Based on what they learn about life here on Earth, astrobiologists are currently trying to answer two big questions:

  • Where should we be looking for extraterrestrial life?
  • How will we know once we’ve found it?

Obviously we can only guess about what alien life might be like, but thanks to the efforts of dedicated astrobiologists, we can now make educated guesses.

Over the next few weeks, as part of the Alien August festivities here on Sci-Fi Ideas, we’ll be taking a closer look at some of the terminology used in the field of astrobiology. This is not meant to be a thorough course in astrobiology but merely an introduction to a few key concepts.

How you choose to use these concepts, either for your Alien August competition entry or to further your research for some other sci-fi project you may be working on, is entirely up to you.

Article by James Pailly. Check out James’ blog for more great science articles.

  • Leonardo Faria

    SETI 2.0

  • Kirov

    Will the difference between astro, xeno, and exobiology be covered? I’ve been told there’s a distinct difference between the three, but I never really understood it.

    • Xeno = Greek xénos, “alien” so technically any life encountered that does not originate from Earth – could be covered under a science named :Xenobiology
      Exo = also Greek = “Outer” any life that originates outside our own bio sphere.
      It’s only semantics and mean the same thing .”Astrobiology” has been chosen to be the official one. but that may change.
      What term to use could be determined by your own (the observers) location. Would all life on Earth for a “Martian” be “Xeno”?
      Or if Stephen Hawkins and a few others are correct and there could be life on a star itself (Camogi, Non Corps of my Universe) the term Astrobiology would no longer be true to all life…
      And if life is truly universal….it might just be called Biology again….

      • Kirov

        I’ve since looked it up and here’s what I understood each term to mean. Astrobiology is the general term as explained here, encompassing a broader spectrum than either xeno or exobiology. Xenobiology is the study of life different from our own, regardless of physical origin (though currently everything on Earth is built on the same basic structure). This would include life that uses something other than DNA to carry genetic information, or is perhaps built on opposite-handed amino acids (I can’t remember if we’re left or right). Exobiology is the study of how life can exist in and interact with other biospheres, so you guessed right on that one, though I think it also includes how Earth life might work on other planets. Of course, I’m going by memory, so I could be wrong.

        • An international body comprised of Universities decide what a “science” is. Where a person can study and obtain academic grades such as a PhD for example.
          Only Astrobiology is (very recently) been approved and acknowledged as such. Neither Exobiology nor Xenobiology are “officially” fields of science or even acknowledged as a sub science.
          But it all boils down to semantics. It also comes down to the very day we find, examine or discover actual life not of Earth. The very definition of what life is might have to be adjusted. For example a computer gains sentience (Self awareness) — is it alive? Is it then a life form? Is it still Biology and Earth based?
          Do Philosophy including Theology and religion have any input on these definitions?
          So I don’t reject your definitions of course and they are not wrong, but they are not clear defined fields of science but rather the definitions of a few scholars that might contradict or reverse their opinions in the next decade.

          In “my” Universe the “left” and “right” chirality of sugars and DNA make a difference (eg what food can be consumed)

          We Humans and all DNA based life on Earth is LDLS (Left DNA helix, left hand sugars) The only “life” not based on DNA on Earth -Viruses (which are “not alive”)